[en] The lifetime of nuclear power plants (NPP) always exceeds the operational time of Instrumentation and Control (I and C) systems. Ageing of I and C equipment in NPPs have many aspects. Research of these aspects is being performed in OKB Mechanical Engineering. Under condition of fast development of I and C systems and applying more stringent safety requirements, modernization of the equipment irrespective of its operational condition is getting important. However, an equipment of I and C systems operated in Russia was designed and manufactured applying highest requirements for a reliability of their work during its whole operational time. Therefore, in many cases it is not necessary to replace them in spite of expiration of their specified lifetime. During operation this equipment is maintained in a proper operation condition by a special service procedures stipulated by its development. When the equipment lifetime approaches to its end, lifetime extension for the certain period should be considered. (author)

[en] Experience has shown that ageing and obsolescence have the potential to cause the maintainability and operability of many instrumentation and control (I and C) systems to deteriorate well before the end of plant life. An I and C ageing management strategy is therefore required to control and minimize this threat. This report gives guidance on how to develop such a strategy and provides examples and supporting information on how established and recently developed maintenance, surveillance, and testing techniques may be employed to support the strategy. In some cases, equipment refurbishment may be necessary and guidance on this subject is given in a companion publication (IAEA-TECDOC-1016, Modernization of Instrumentation and Control in Nuclear Power Plants, IAEA, Vienna, 1998). The International Working Group on Nuclear Power Plant Control and Instrumentation (IWG-NPPCI) of the IAEA proposed in 1995 that a technical report be prepared to provide general guidelines on the management of ageing of important I and C equipment in nuclear power plants. The purpose of the report would be to guide the worldwide nuclear industry on potential effects of I and C ageing on plant safety and economy, and the means that are available to help minimize or eliminate any detrimental consequences of ageing. In response, a consultants meeting of five experts from Finland, France, Germany, the United Kingdom and the USA was held by the IAEA in Vienna in September 1997 to exchange national experience on the subject and to discuss the possible content of the report. The group of experts was tasked with bringing together all the information that is available on I and C ageing and ageing management methods. After a thorough discussion and analysis of the available information, an extended outline of the report on the subject was produced. The purpose of the extended outline was to identify a structure of the report, bring together information available at the moment and to provide guidance in the developing of a full-scale report. The extended outline was then elaborated by a working team into a first draft report during the period September 1997 to February 1998. This draft served as a working document during an IAEA advisory group meeting held Vienna in April 1998. In this meeting, additional advisors from the Czech Republic, India, the Russian Federation and Slovakia provided recommendations and additional material that has been included in the report. The final consultants meeting was held in Vienna from 28 September to 2 October 1998. This report provides a review of ageing characteristics of representative nuclear power plant instrumentation and control (I and C) equipment and describes some of the technologies and procedures that are currently available for management of ageing of this equipment

[en] This paper describes three successive studies on ageing of protection automation of nuclear power plants. These studies were aimed at developing a methodology for an experience based ageing analysis, and applying it to identify the most critical components from ageing and safety points of view. The analyses resulted also to suggestions for improvement of data collection systems for the purpose of further ageing analyses. (author)

[en] This country report is based on data collected within working committees of VGB Technical Association of Large Power Plant Operators, Essen, Germany, namely the report 'Ageing Diagnosis, Prediction and Substitute Strategies for I and C' by R. Heinbuch, J. Irlbeck (Bayernwerk Kernenergie AG Muenchen) and W. Bastl (Institut fuer Sicherheitstechnologie GmbH Garching). It was compiled in its current form by L. Mohrbach, VGB Headquarters, in his capacity as member of the IAEA Advisory Group on Nuclear Power Plant I and C Equipment: Periodical Testing, Evaluation and Maintenance Strategy. (author)

[en] This report presents a brief perspective on the management of Instrumentation and Control (I and C) ageing in UK NPPs. It does not address the issues of refurbishment strategies, the use of digital I and C or the technical details of advanced monitoring techniques. These items are discussed in other country reports and elsewhere in this TECDOC. (author)

[en] Advanced sensors and new testing and maintenance technologies have become available over the last ten years for nuclear power plants (NPPs) to replace outdated, obsolete, and troublesome instruments, provide for management of ageing of critical plant equipment, optimize maintenance activities, reduce maintenance costs and personnel radiation exposure, and at the same time, improve plant safety and availability. These new developments are reviewed in this TECDOC. The material covered here has been summarized from NUREG/CR-5501, a 1998 report written by H.M. Hashemian and his co-authors for the US Nuclear Regulatory Commission. (author)